The invention relates, to a motor vehicle group transmission with an input shaft, an intermediate shaft and a main shaft arranged in succession and coaxially with one another and parallel to a countershaft.
Lechner, G., “Fahrzeuggetriebe” [“Vehicle transmissions”], Springer-Verlag, 1994, pages 154 to 158 already discloses the three-group transmission 16 S 109 of the company ZF FRIEDRICHSHAFEN AG and the twin-splitter transmission of the company Eaton.
The three-group transmission 16 S 109 comprises an input shaft, an intermediate shaft and a main shaft. The first two toothed stages are designed as input constants. Here, the drive gearwheel of the first input constant is a loose wheel disposed coaxially on the input shaft. The drive gearwheel of the second input constant is, in contrast, a fixed wheel disposed coaxially on the intermediate shaft. The intermediate shaft can be rotationally fixedly coupled by means of two gearshift clutches to the input shaft and to the main shaft, such that a direct gear is established. With the exception of the gearwheel stage of the reverse gear and the range group, said three-group transmission requires five gearwheel stages to realize sixteen forward gears. Also, the twin-splitter transmission has two countershafts.
DE 102 39 396 A1 relates to a countershaft transmission with a direct gear whose countershaft does not co-rotate when the direct gear is engaged.
U.S. Pat. No. 5,381,703 also relates to a countershaft transmission having an input shaft, an output shaft and a countershaft, with the drive of the countershaft being prevented when the countershaft transmission is in the direct gear.
It is the principal object of the invention to provide a utility vehicle transmission which is relatively short but has a high number of gears.